Effects of Biopesticides and Undersown Cover Crops on Soil Properties in the Organic Farming System

Abstract

The inclusion of undersown cover crops in crop rotations and the use of biopesticides are essential for the long-term sustainability of the agroecosystem in organic farming. We hypothesized that biopesticides and undersown cover crops (crimson (incarnate) clover (Trifolium incarnatum Broth.), hairy (winter) vetch (Vicia villosa Roth.), perennial ryegrass (Lolium perenne L.), and winter rye (Secale cereale L.)) are likely to have a positive impact on soil agrophysical and biological properties. Soil shear strength, soil aggregate–size distribution, plant root dry biomass and number and biomass of earthworms were determined at the end of the plant growing season. We concluded that the application of biopesticides and growing of undersown cover crops decreased soil shear strength and increased the percentage of macro-aggregates (0.25–10 mm) in the plough layer. In the plots with cover crops, plant root biomass was found to be significantly higher by a factor of 1.9 to 3.5, compared to the plots without cover crops. The application of biopesticides and undersown cover crops did not significantly affect the number and biomass of earthworms in the soil. The abundance of earthworms was more influenced by meteorological conditions.